Camping at Gross Reservoir. Photo by Michael Swadener

Gross Reservoir: Boulder’s Hidden Gem Where You Can Camp


This campsite is everything. First, it’s in Boulder County, about 40 minutes up Flagstaff Road from downtown Boulder. It’s one of the rare places to camp in the Boulder area; there are no actual campgrounds the city limits. 

Second, it’s a peaceful hidden gem with minimal traffic. You may very well be the only camper here. Even on camp-crazy days like Memorial Day weekend, the trailhead’s rarely busy, making it one of the best places to visit in Boulder.

Third, it’s totally free.

Gross Reservoir, tucked in a scenic canyon, is our favorite secret camping spot close to home — so good that we almost didn’t share. But here we are with details of our favorite point of interest in Boulder. You lucky dog.

Before you set out on a camp-cation to Gross Reservoir, there are some things you need to know.

Camping at Gross Reservoir. Photo by Michael Swadener

The Overview

Gross Res is a stunning alpine body of water that is open to the public for free. You can go fishing, hiking, camping, paddling and picnicking here; take out a boat, too, but no motors allowed.

Likewise, camping is primitive. There are no RV hookups. This is a rugged spot for tents, but make sure you’re in the right spots.

Gross Reservoir is perched at 7,500 feet above sea level, located above Boulder along the South Boulder Creek Drainage. The cold-water reservoir has 440 acres of surface area, some that stretch out into isolated “fingers.” The lake itself gets deep (300 feet). Gross boasts 10 to 14 miles of shoreline (depending on who you ask).

Surrounding the water, you will see granite outcroppings, snowy mountaintops in the distance and plenty of pine trees. The reservoir, formed by an impressive, 340-foot-high concrete dam on the creek, is nestled into the foothills. The water here comes from the western slope.

Visitation details: Gross Reservoir is open year-round sunrise to sunset, but specific activities have limited windows. The west side is closed late fall through early spring. The lake is open to boating from around Memorial Day through late September. There may be additional closures when construction starts (see below).

Directions: From Boulder, it’s easy. Just take Flagstaff Road west until it turns into eastern Gross Dam Road.


Gross Reservoir was finished in the mid-1950s. It wasn’t until recently that it opened up for public paddling. The reservoir is water storage and also regulates water flow below the Continental Divide.

The east side of the reservoir is owned and operated by Denver Water. The west side is managed by the Roosevelt National Forest’s Boulder District. That’s the side you want to keep in mind for camping.

The reservoir was named after Denver Water’s former chief engineer Dwight D. Gross.

There’s a project to expand the reservoir for the future. It would raise the level of the dam by 131 feet, making it the tallest dam in the state (as well as the largest public works project in Boulder County history). Construction is expected to be done around 2025. The project is controversial, though, because it would mean removing many trees.

The Gross Reservoir area. Photo by Michael Swadener


Here are some of the ways you can use Gross Reservoir.

Fishing: The Colorado Division of Wildlife stocks the reservoir with cold-water fish (rainbow trout, brown trout, lake trout, splake, kokanee salmon and tiger muskie). The best places to fish are below the dam, near the inlet and within the body of water. You can also fish off much of the shore. You can ice-fish here in the winter when conditions permit.

Picnicking: Gross Reservoir has four different picnic areas: North Shore, South Shore, Miramonte and Windy Point. Find restrooms, parking and sheltered picnic tables on the east side of the water. This side of the lake is for day use only. The reservoir is big enough that you can likely eat in privacy.

Hiking: There are several hiking options here. Take the North Point picnic area to get to the reservoir. Follow the South Shore Recreation Area trailhead to the South Boulder Creek Inlet.

One fun hike in this area is to take the Forsythe Canyon to the waterfall and end at the reservoir. This two-plus-mile round-trip hike is shady, rarely busy and easy-to-moderately difficult. It may be appropriate for kids. It’s pretty spectacular, with the small waterfall, wildflowers, the stream, canyon and ending with the alpine water. Find the Forsythe Canyon Trailhead from Lakeshore Road (not Magnolia Road).

Water access: No swimming, diving, wading or otherwise splashing. If you want to get in the water, you have to stay on the water, in a non-motorized boat. Stand-up paddleboarding is OK. Non-motorized boats (like canoes and kayaks) are permitted in late May through the end of September, sunrise to sunset. Leave your sailboat, trailer-hitched boat and motor boat at home.

Paddling can be challenging here due to the wind spilling off the Continental Divide. And the water is frigid. The reservoir is remote and has limited facilities, so come prepared. Weather can change quickly and get extreme.

If you’re still up for it, the views and solitude can be worth it, especially if you find your way into one of the private, little fingers of the lake.

The boat put-in is on the south shore at Osprey Point.

In the winter, some people go ice-skating here, but it’s done at your own risk. It can get really windy here, and the sharp wind plus icy conditions can be rough.

Bouldering: You can find bouldering opportunities on the east side of Gross Dam Road, southeast of the water.

Michael Swadener camps at Gross Reservoir. Courtesy photo


Yes, you can camp. But it’s primitive. And only allowed on the west side of the lake in the Roosevelt National Forest.

This area has about 20 campsites scattered throughout the trees. They’re all marked with a number and have a fire ring, although fires may not be permitted. You must currently keep fires in grills and fire grates. (There was a small wildfire near the reservoir in June. No cause was released.)

Camping is free and there are no reservations. It’s first come, first served. You can camp from Memorial Day until the first snowfall; campsites are closed seasonally. Before heading out, check with the Boulder District to make sure conditions are safe and it’s open.

You will need a high-clearance vehicle to get access to this area via a bumpy dirt road on the west side. Take Magnolia to Colo. 68 and take that to Forest Service Road 359. There is no access from the east side (on Lake Shore Drive), no matter what Google Maps insists. It’s lying.

You cannot camp on Denver Water’s side of the reservoir.

8 Responses

  1. Nice campsites – All full when we went on a mission to scope it out on Friday, 8/2/19. There are additional walk in sites as well bringing the number to 31. The note above on getting in from Lake Shore Drive is not totally accurate. You can get through there (we did it yesterday after confirming with the ranger that it’s legal). Be warned – IT IS SERIOUS 4 WHEELING with 2 to 3 foot ruts, rocks and drop offs and a sign that reminds you that getting towed out will be very expensive if you get stuck. Magnolia is a much better way to get in. We saw a number of car-based SUVs that made it in that way without trouble.

  2. Are tubes allowed on the water for floating not swimming? If there is a fire ban can you have a fire with a fire grate?

  3. Construction and confusing directions had us all over the place. Rough roads and orange cones have some of the roads blocked off, which were our directions to follow. We arrived at the dam and there was no spots to fish. We still had fun. Beautiful lake. It was just hard to believe there was so many people on a week day.

  4. My close friends and I have been coming here for the last 11 years it started as such a great tradition that we all started in college and would always come back to as life went on and we went to different schools and states and careers. On our first 7 trips we were almost always alone and it was so wild and free. Being a group that is dedicated to dispersed style camping this was perfect, overgrown trails, wild animals, and just clean and fresh feeling. Nothing but a fire ring and a sign. But as the years went on we started to see less and less wildlife both animals and brush/ grass where the sites were. More and more cars being parked where they shouldn’t leading to just a more paid campsite/ KOA style feel to the area which brought down the mood for us trying to get away from that style of camp. The nights used to be an experience to die for, being so quite and slightly spooky being so alone but now it’s a car coming up to your campsite with headlights every few hours looking for a spot because it’s full. I am not one to complain but it seems what used to be a hidden gem is now far from that. Thank you overpopulation maybe we’ll see what Montana is like.

    1. Perhaps you should seek more solitude in Antarctica. Hopefully I was camping there when you and you buddies were. I’d hate to be the cause of the experience you described. Yes, please move to Montana for your future trips.

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